Ice preventing means for propellers



Feb. 10, 1948. I DE STEFANQ 2,435,712

ICE PREVENTING MEANS FOR PROPELLERS Filed May 2, 1945 3 Sheets-Sheet 1 In w Inventor WW Em 1948. .1; DE STEFANO D 2,435,712

ICE PREVENTING MEANS FOR PROPELLERS Filed May 2, 1945 s Sheets-Sheet 2 B, @AwaaEa-L WW 19m 1948. J. DE STEFANO 2,435,712

.' ICE PREVENTING MEANS FOR PROPELLERS Filed May 2, 1945 3 Sheets$heet 3 Patented Feb. 10, 1948 My invention relates to-propellers for airplanes, seaplanes, helicopters andg dirigibles, and more specifically to propeller de-icing apparatus of the type forming the subject matter of my U. S. Letters Patent No. 2,339,772, dated January 25,

1944, and over which the instant invention is designed as an improvement.

The primary object of the instant invention is -to provide de-icing apparatus for such propeller blades especially adapted for discharging de-icing fluid forwardly of the blade along the leading edge thereof to effectively de-ice the leading edge andbe thrown rearwardly and outwardly toward thetip of the-blade sons to form- 'a film over the entire blade.

Another object istoprovide de-icing apparatusequipped with means for distributing de-icing fluid over the root end of the blade in case the apparatus fails tofunction as above set forth, or .while the apparatus is so functionin and so that th'ede-icing fluid will be'thrownun'der the action of centrifugal force outwardly" along the entire blade and directed toward the leading edgeof said blade.

Still another object is to provide in such de- -icing'apparatus for directing the ole-icing fluid discharged forwardly of the blade outwardly along the leading edge tothetip of the blade so as to efiectively de-ice'saidedge.

Another object is'to provide apparatus adapted to function 'efiiciently in the manner set forth and whichis of simple construction rendering the same inexpensive to manufacture and replace,

Gther and subordinate objects, also comprehended by myinvention, together with the preoise nature of my improvements, andthe manifold advantages thereof, will be readily understood when the succeeding description and claims are read with reference to the drawings accomblades embodying the invention and drawn to an enlarged scale,

Figure 3 is a similar-"fragmentaryview with parts shown .in section :and drawnto a further enlarged scale,

Figure 4 is a-detail -view 'in1transverse section taken on the line 4-:.-:4 of Figure 3,

Figure 5 is aview in-plan'ot'the de icingrboot --detached and shown in aspread-outzcondition,

:Figure 6. .is 2a view similar to." Figure :2 .i11us trating a modification otthe invention, 7

4 Claims. (Cl; 244-134) Figure Tis a viewin transverse section taken onthe lined-1 oifiEigure 6 and drawn to anen- 'larged scale.

Reference beinghad tothedrawings by numerals,and first toFig'uresil t05 thereof,ithe'ti/ D :0I

propeller shown as embodying :my improvements comprises a hub i eguipped with a'concentrlc socalled slinger ring "2' rotating'With the hub and I havingformed in the outer face thereof an annular groove '3 capped -an-annular stationary shield 4, secured to theimotm not shown, by bolts 5, the groove '3 :a-ncl the-shieldd forming a chamber for de-icing*iiuid to-bethrown, under the action of centrifugah'iorce. out of said ring "2 through nipples, --'as at '6, on-the slinger ring 2. The nipples 6,{f or "instance asbest shown in Figure3, are aligned,substantially, with the leading edges of the propeller blades 1. The blades '1 are mounted in blade-sockets Son thehub I. Deicing fluid, not shown,"is supplied to the grooved, or chamber. by a-forcedfeed supply plant 9, 'usu'ally 'located in-the cockpit of an airplane, not shown, and including a iluid supply line l0 suitably connectedto the shield 4.

According to theinstant invention, the blades 1' are each provided *withsan elongated, clip-like "boot ll fitting over the leading edge 12 of the blade I in straddling relation thereto and extending from the root',or base,-end 13 of the blade to substantially-thetip end 14 of said blade. Each boot I [comprises a'pairof side flaps l5 diverging from what constitutes the leading edge 15 of the boot and tapering from substantially said edge l6, as best shown in Figure-4. At the inner end of the boot ,theflaps i5 are-widened to provide "a split cuff portion l1 adapted to completelysurround the root, or-base, endportion i3 of the blade 'I. The leading 'edge [6 of each boot H is thickened and terminates adjacent to the inner end of said bootinamanifoldnipple l8 opening into the inner ends of a series of closely spaced small ducts 1 9 extending through said leading edge 16, longitudinally. Preferably. and as shown imFigul'e 4,- threessuch; ducts l9 are provided, with one duct extending. along thetlongitudinalcenter "oi the leading edge It to within .a short distance of: the tip'end of the boot H and the other" ducts '19. extending alongside the first-mentioned duct and; as bestshownlinFigure 5,2branching into the first duct atdifferentidistances from the manifold -nipple"-l8 opposite smail outletportstll from the rfirstrmentioned duct opening onto the leading ,edge l6 in' the exact-longitudinal center thereof. .1 t oonnection ether outlet ports-,2! fromvthe .iflrst-mflhtiOXlBdfldmt :4 were similarly; provided an the leading edge I6 and said ports", 2| are equidistantly spaced apart along said edge, A pair of small ribs 22 extend along the leading edge I6 upon opposite sides of the longitudinal center thereof and from the manifold nipple I8 to the tip end of the boot said ribs 22 being spaced close together to provide a narrow shallow channel 23 along the leading edge l6 into which the outlet ports 20, 2| open for a purpose presently seen. A series of small external ribs 24, which may vary in number as desired, extend diagonally across the cuff portion II from the trailing edge of said portion and the inner end of the boot to the leading edge It of said boot I I adjacent the manifold nipple I8, said ribs preferably converging relatively toward said edge. The function of the ribs 24 will presently be described.

A fluid feeder line 25 connects the manifold nipple of each boot II with the adjacent nipple 6 with a coupling interposed therein forming a back-pressured discharge valve. The coupling 26 comprises a tubular body 21 having an axial bore 28 therein for feeding fluid therethrough to the manifold nipple l8, and an enlarged central portion 29 provided with longitudinal fluid return ducts 30 therein grouped around the bore 28, said ducts opening into a tubular sleeve 3| connecting the portion 29 to the manifold nipple I8, said ducts 30 having lateral, rear end outlets 32 opening into an annular forwardly flaring spreader 33 surrounding the portion 29. A tubular sleeve 34, similar to the sleeve 3| connects the coupling 26 to the nipple 6, the sleeves 3| and 34 being arranged at opposite sides of the spreader 33 so as to leave the spreader 33 exposed. The arrangement of the coupling 26 is such that the same is close to the cuff portion I! and the spreader 33 opens toward said portion.

The entire boot described is preferably formed the fluid is discharged through the outlet ports 20, 2| into the channels 23. The de-icing fluid being supplied under suflicient pressure, overflows out of the channels 23 to be distributed, by

revolution of the blades I and under the action of centrifugal force, over the flaps I5 and the exposed portions of the blades 1. Also, the deicing fluid is caused, under the action of centrifugal force, to flow along the channels 23 toward the tip ends of the blades 1, thereby facilitating distribution of the de-icing fluid over the flaps l5 and blades I to the tip ends of said blades. Should the discharge ports 20, 2| become clogged, for any reason, the de-iclng fluid will back up in the manifold nipples l8 and the sleeves 3| and discharged through the ducts 30 and ports 32 'into the spreaders 33 and be directed by said spreaders onto the cuff portions H. In this event, the de-icing fluid will be thrown under the action of centrifugal force along the flaps l5 and blades 7 toward the tips I of said blades and also be directed by the ribs 24 to the leading edges I 6 of the boots to flow along said leading edges toward the outer ends of the boots'll.

f Thus, the de-icing operation will be effected in- 4 dependently of the ducts l9 and outlet ports 20,-

2| in the event that such ducts and outlet ports fail. However, by supplying the de-icing fluid to the groove 3 under pressure such that the dis-' charge is choked at the outlet ports 20, 2|, the described de-icing operation effected under back pressure may also be accomplished in conjunction with de-icing through the ducts 9 and outlet ports 20, 2|, the advantage of which will be obvi-5 ous, particularly where heavy sleet storms and the like are encountered in navigating aircraft.

In the modification of the invention shown in Figures 6 and 7, the construction and arrangement is substantially the same as that previously described, with the exception that the boot 35 has the form of a cuff completely surrounding the propeller blade 36 for the greater portion of its length, as shown.

The foregoing will, it is believed, sufiice to impart a clear understanding of my invention without further explanation.

Manifestly, the invention, as described, is susceptible of modification without departing from the inventive concept, and right is herein reserved tosuch modifications as fall within the scope of the appended claims.

What I claim is:

1. In a propeller for airplanes and the like, a hub including a storage chamber for de-icing liquid, a propeller blade on said hub, a de-icing boot fitting over said blade and having a leading edge extending along the leading edge of the blade, longitudinal ducts in the leading edge of said boot terminating in outlet ports spaced apart along the leading edge of theboot, means common to all of said ducts for establishing communication between said chamber and the ducts comprising a manifold on the leading edge of the boot and from which said ducts extend, an ex-- posed liquid feeder line from said chamber to said manifold, and a device in said line for discharging de-icing liquid onto said boot adjacent the root end of the blade under back pressure in said ducts.

2. In a propeller for airplanes and the like, a hub including a, storage chamber for de-icing liquid, a propeller blade on said hub, a de-icing boot fitting over said blade and having a leading edge extending along the leading edge of the blade, longitudinal ducts in the leading edge of said boot terminating in outlet ports spaced apart along the leading edge of the boot, means common to all of said ducts for establishing communication between said chamber and the ducts comprising a manifold on the leading edge of the boot and from which said ducts extend, a liquid feeder line from said chamber to said manifold, a device in said line for discharging de-icing liquid onto said boot adjacent the root end of the blade under back pressure in said ducts, and means on said boot for directingrthe de-icing liquid discharged onto said boot diagonally thereof toward the leading edge of the same under the action of centrifugal force.

3. A de-icing boot for use on a propeller blade comprising a, clip-like elongated member adapted to straddle said blade and having a leading edge portion adapted to extend along said edge of the blade, longitudinal ducts in the leading edge of the boot terminating at one end in outlet ports spaced apart along the leading edge of the boot, a manifold nipple on said leading edge of the boot adjacent one end of the boot and opening into'the other ends of said ducts, said nipple being adapted for introducing de-icing liquid into said ducts, and a pair of ribsextending along said leading edge of the boot and forming a channel into which said ports open.

4. A de-icing boot for use on a propeller blade comprising a clip-like elongated member adapted to straddle said blade and. having a leading edge leading edge of the boot and forming a channel 15 2,381,331

into which said ports open, said boot having a cuff portion at one end thereof adapted to surround the root end of a propeller blade.

JOHN DE STEFANO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,269,635 Mosehauer Jan. 13, 1942 2,334,118 Morse et al Nov. 9, 1943 '2,354,764 Martin Aug. 1, 1944 Brown Aug. '7, 1945 

